The invention relates to a clamping device for paper sheets of the type having a clamping device, particularly for a clamping file, having an essentially U-shaped cross-section with a first and a second leg connected with one another by way of a back, said legs being elastically pressable apart on their free longitudinal edges to define a clamping gap therebetween for the inserting and clamping-in of one or several paper sheets. The invention also relates to a clamping file which is provided with such a clamping device and has two file covers which are connected with one another along a folding edge.
By means of files of this the, one paper sheet or a plurality of stacked paper sheets may be releasably fastened in the file by means of clamping, without the requirement of carrying out measures on the paper sheets, such as perforating, which often result in undesirable and irreparable changes of the sheets. Clamping devices and clamping files of the initially mentioned type are known, for example, from German Utility Model Documents DE 89 09 989 U1 and DE 89 10 130 U1. In the case of the files of these documents, the clamping device is displaced in a linear uniform motion perpendicularly to the folding edge of the clamping file in the area of its window between a clamping position and a releasing position. So that the clamping device can be held on the file also in the releasing position and cannot be lost, lateral projections or thickenings, which interact with the folding edge, or counterhooking strips are provided along the folding edge area embraced by the clamping device. Even in the releasing position, the clamping device therefore reaches, by means of its clamping free longitudinal edges, around the back file cover as well as a lamellar part arranged on the front side in the window area, along its folding edge. For facilitating the first sliding-on of the clamping device, the free longitudinal edge of the upper leg may be provided with an oblique surface which forms, together with the lower clamp leg, a mouth which opens up in a V-shape and extends along the whole length of the clamping device, the free longitudinal edge of the lower leg projecting beyond that of the upper leg.
In addition, a clamping file is already on the market in which the pertaining clamping device is pivotally connected to the back cover of the file. In the case of the clamping device used here, the free longitudinal edges of the clamp legs, which define the clamping gap between one another, extend at a narrow constant distance from one another along their whole length. The two clamp legs are connected with one another by way of a continuous back, and the lower leg has a lengthening on a face end, which lengthening contains an opening by means of which the clamping device is swivellably held, for example, riveted on, on the back cover of the file. From its clamping position, in which it is situated inside a window cut out of the front cover of the file, the clamping device may be swivelled out by approximately 90.degree. into a releasing position in which it completely releases sheets which were previously clamped in and inserted in the file and, in particular, file parts are no longer situated in the clamping gap between the free longitudinal edges of the clamp legs.
The invention is based on the technical problem of providing a clamping device as well as a clamping file equipped therewith which permits a convenient and trouble-free handling of the clamping device in which the clamping device cannot be lost as well as a releasing of inserted clamped-in sheets in the different usage conditions of the file.
This problem is solved by means of a clamping device wherein the free longitudinal edge of the first leg is formed at a distance from the free longitudinal edge of the second leg in the area of a face-side end as a paper sheet accommodating inserting mouth, which distance increases in the direction of this face-side end.
By the formation of the inserting mouth in the area of the face-side end of a clamp leg, the parts which are to be clamped in can conveniently and reliably be entered into the clamping device without any abutting by the parts to be clamped in against the free longitudinal edges of the legs which define the clamping gap. During continuous use, this abutting may result in damage to the file in its folding-edge-side area.
The arrangement of such an inserting mouth is particularly advantageous in combination with a swivellable connection of the clamping device with the clamping file which is provided as a lengthening of this face-side end, because then the file cover or covers together with the sheets situated in the interior are automatically inserted at the front into the inserting mouth of the clamping device when the clamping device is swivelled from a releasing position into the clamping position. The inserting mouth is therefore used as an insertion aid not only when the clamping position is established for the first time but also in all other subsequent clampings during the use of the clamping file.
In a further development of the invention, the back has a shortened design, whereby a slot is created. As a result, even when the clamping folder is folded open, the clamping device may still be swivelled out of the clamping position so far, for example, by 45.degree., that the previously clamped-in parts, such as the rear cover of the file, a front-side lamella part and paper sheets disposed in-between, are only still situated in the area of the inserting mouth inside the clamping device so that there is no longer any clamping effect and the sheets may be removed and new sheets may be inserted.
In a further development of the invention, a recess is provided on the back-side longitudinal edge of the leg containing the devices for the swivellable holding. Thus, it is achieved that, also in the folded-over condition of the clamping file in which the two outer sides of the file cover rest against one another, the clamping device can be swivelled out so far, for example, by an angle of between 20.degree. and 50.degree., that the previously clamped-in parts are only still situated in the area of the non-clamping inserting mouth and the inserted sheets can be exchanged again. When the clamping device is swivelled out, the border of the folding edge which is closer to the swivelling axis and borders on the window area enters into the recess which permits the swivelling-out of the clamping device about an angle required for the release of the sheets. Damage to the folding edge in this area by the swivelling-out of the clamping device is preferably avoided by the fact that, on its side facing the devices for the swivellable holding, the recess is bounded by a linear section of the longitudinal edge of the second leg which is assigned to the back, which section forms an acute angle with the longitudinal direction of the back. This causes a material-saving, line-type striking of this linear clamp section against the folding edge when the clamping device is swivelled out.
For aiding the swivel movement between the clamping position and the releasing position, it is advantageous to arrange handling knobs on the half of the clamping device which faces away from the swivelling axis, which handling knobs provide a gripping surface for the swivelling-out and swivelling-in.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.